I'm trying to use the sample code associated to the talk Author fragmented MPEG-4 content with AVAssetWriter which can be found here. It works well when I run it on macOS, but after adapting it to run in iOS (basically moving the code in the main file to a view controller), it doesn't work. The problem is that the function: assetWriter(_:didOutputSegmentData:segmentType:segmentReport:) is never called for the last segment. In macOS, the last segment is reported after calling the function AVAssetWriter.finishWriting(completionHandler:), but before the completionHandler parameter block is invoked. In iOS, nothing happens at that point. Is there anything I could do from my side to fix this problem? Thanks in advance!

According to the Apple docs, you should be able to connect audio nodes to an AVAudioEngine instance during runtime, but I'm getting a crash while trying to do so, in particular, when trying to connect instances of AVAudioUnitTimePitch or AVAudioUnitVarispeed to an AVAudioEngine with manual rendering mode enabled. The error message I get is: Terminating app due to uncaught exception 'com.apple.coreaudio.avfaudio', reason: 'player started when in a disconnected state' In my code, first, I configure the audio engine: let engine = AVAudioEngine() let format = AVAudioFormat(standardFormatWithSampleRate: 48000, channels: 2)! try! engine.enableManualRenderingMode(.offline, format: format, maximumFrameCount: 1024) try! engine.start() Then, I try to attach the player to the engine: let player = AVAudioPlayerNode() configureEngine(player: player, useVarispeed: true) player.play() // this is the line that causes the crash Finally, this is the function I use to configure the engine nodes graph: func configureEngine(player: AVAudioPlayerNode, useVarispeed: Bool) { engine.attach(player) guard useVarispeed else { engine.connect(player, to: engine.mainMixerNode, format: format) return } let varispeed = AVAudioUnitVarispeed() engine.attach(varispeed) engine.connect(player, to: varispeed, format: format) engine.connect(varispeed, to: engine.mainMixerNode, format: format) } If I pass false as the value for the useVarispeed parameter, the crash goes away. What is even more interesting is that if I add a dummy player node before starting the engine, the crash goes away too 🤷‍♂️ Could anyone please add clarity on what's going on here? Is this a bug or a limitation of the framework that I'm not aware of? Here's a simple project demonstrating the problem: https://github.com/rlaguilar/AVAudioEngineBug